Color television



March 13, 1951 I 5. J. KOCH E/TAL COLOR TELEVISION 2 Sheets Sheet 1Filed Dec. 26, 1946 FIG. 2

March 13, 1951 s. J. KOCH ETAL 5 5 COLOR TELEVISION 4 Filed Dec. 26,1946 I 2 Sheets-Sheet 2 FIG.3 3

OQQOQOOOO000.000.06.606.

PIC-L4 3 DOOOQQQQQOOQ QOOQQOQQQOQOQQQOOQ4 Patented Mar. 13 1951 UNITEDSTATES PATENT OFFICE COLOR TELEVISION Stanley J. Koch, Clifton, andRobert E. Ruther-' ford, Nutley, N. J.,' assignors to Allen B. Du MontLaboratories, Inc., Passaic, N. J., a corporation of DelawareApplication December 26, 1946, Serial No. 718,364

This, invention relates to color television. It relates particularly tocolor television in which provision is made for transmitting the threecolors red, blue and green simultaneously.

6 Claims. (Cl. 250164) In carrying out the invention provision is madefluorescence, when scanned with the beam of a for applying colorresponse material on surfaces cathode-ray tube, one giving redfluorescence, and that are at angles to each other. Cathode-rays onegiving blue fluorescence, for example. The are provided to scan therespective color resize of these faces are such that a single group issponse materials. Three sets of surfaces are proequal to or smaller thanthe scanning spot as norvided with the surfaces of each set parallel tothe mally used to provide a predetermined size teleother surfaces ofthat set and substantially pervision picture. pendicular to the surfacesof the other sets. Each gun 4 is a source of light, that is, one gun Theinvention may be understood from the excites the red fluorescentmaterial on faces 5, description in connection with the accompanyinganother gun excites the green fluorescent madrawings in which: 7 l5terial on faces 6, and the third gun excites the Fig. l is a side viewof an illustrative embodiblue fluorescent material on faces 1. Thus byment of the invention, showing a cathode-ray applying color televisionsignals simultaneously tube. from a color television transmitter sourcein the Fig. 2 is a rear view of the cathode-ray tube known way to therespective guns the three shown in Fig. 1. colors are combined or mergedin the faces 5, 6

Fig. 3 is a plan view of enlarged elements showand l of the screen 3 toproduce colored pictures. ing a screen for said tube. This arrangementcan, by keying in the known Fig. 4 is an edge view of Fig. 3. way, alsobe used with sequential colored tele- Fig. 5 is a plan view on anenlarged scale showvision systems by applying the proper color seing asmall portion of Fig. 3. quence to the grids of the respectivecathode-ray Fig. 6 is a cross section on a larger scale along tube guns4. the line aa of Fig. 5 showing the aluminum It will be understood fromthis description that backing of the fluorescent screen. the angle atwhich the electrons strike the 7 s an edge view of a modification offluorescent surfaces 5, 6 and 1, is critical. The Fig. 4. 3O electronsfrom guns 4 should strike their respec- In he drawin s referenc ch ra er1 indi a s tive surfaces in a direction that is perpendicular a glassnvelop r u upon the i i f c 2 of or substantially perpendicular to thesesurfaces which is located a screen 3 to be described more i der t btainthe best results. in detail below. This screen 3 may be placed It hasbeen found to be advantageous to apply upon the inside face 2 of thetube I or the screen a Very thin layer 9 (Fig. 6) of evaporated aluy beembodied in the inside Surface of the minum to the fluorescent surfaces5, 6 and l. face 2. When such a thin aluminum layer 9 is applied Threecat odey u s 4 are arranged at to the surfaces 5, 6 and I the electronsthat strike angles to the c 2. e Screen is provided W perpendicularly tothe aluminum surfaces will three sets of parallel faces and eachcathode-ray 40 penetrate th m i it readfly a d thu un 4 is so locatedthat its beam strikes only on excite the fluorescent material on thesesurfaces, s t f th parall l fac of the s These but the electrons thatstrike at an acute angle to c y guns 4 are located in positions to thesurfaces will not penetrate to the fluorescent p j c their Cathode-raysperpendicularly material due to the greater length of aluminum su santial y p p d u ly n the three path through which they traverse atacute angles. spective surfaces of the screen which the beams h 1 t fromany one of th guns 111 of these guns scan. 7 penetrate the faces whichare perpendicular to A glass pl 3 is shown in Fi 3 to 6 havin theelectron beam of such a gun, but the eleca pattern of depressions andprojections protrons from the same beam which strike the other duced byembossing as shown in Fig. 5 on an enfaces will strike them at a veryacute angle, and larged scale. Each one of these projections has becauseof the presence of the aluminum layers three faces 5, G and I to whichscreen material they will not excite the unwanted colored fluohavingdifferent color response characteristics rescent materials under theselayers. When such is applied. Each one of the faces 5, 6 and l, is atlayers are used the guns can be brought closer approximately 90 to eachof the other two faces. together and in this way the need for correctionfor the registry of the patterns due to the various angles of the gunsis decreased. A further advantage of the aluminizing using thereflection phenomena of the aluminum surface allows the tube to beviewed from a greater angle than otherwise would be the case, that is,the group of facets 'beinggmirrored by the aluminum reflects thelightjfromzthe opposite facets. .For example, surfaces which producegreen light will also :be reflected from the other surfaces 6 and I sothat the viewer from the far side who would not otherwise see the equalarea of the green facet sees by reflection the desired amount :of thegreen color. This applies-to all three colorsso that there is not only alarger viewing angle for registering the proper colors, but there isalso a better mixing of the colors .by reflection of the various lightswithin the facets themselves.

This larger viewing angle can be improvedby providing lenses 8 (Fig.2?)on the front side ofthe screenshownin Fig. 3,-each lens being the sizeof a group of three colors represented ,by reference characters 5,-6.andI. This improvement in the viewing angle comesabout by .virtue of the.ability of the lenses to assist in the concentrationiof the three beamsof light from the three sets of facets 5, 6, and 1 into one .beamoflight maintaining "a goodcolor balance over a wider ,angle than is,possible without the lenses.

-What isclaimedfis:

1. A color selection screen; embossments on said screen; facets. on saidembossments; said embossments jbeingarranged so that eachfacet oneachembossmentis substantially parallel ,to

a corresponding faceton adjacent embossments whereby a plurality of.groups .of surfaces is formed; a fluorescentcoating on said screen,said coating beingcomposedof diiferentmaterials on said groups .ofvsurfaces, each .of said materials beingadapted to..emit' light ofadilferent color than the othersof said materials whenexcited byelectrons; and ametallicllayer ,coveringsaid fluorescent coating, .saidmetallic layer being permeable .to electrons that. strike it essentiallyperpendicularly .and impermeable .to electrons striking it substantiallytangentially.

v2.. In a color television system, a vacuum .tube

havinglascreen with .alfluorescent surface and a plurality of,.electrongunsfor generating electronbeams forscanning said .screen; embossmentson oneside of said surface, said embossmentsforming aplurality of setsof fluorescent surfaces angularlydisposed with respect to, each.otherand positioned ,to bestruck respectively ,byindividual ones ofsaid electron beams; and

metallic coating beingpermeable only to electrons striking itessentially perpendicularly; and

three electronguns located sothat the electrons fromeach one of saidgunsstrikes one of said portions substantially perpendicularly.

4..A ffluorescent screen comprising a lightpermeable plate embossed ononesurface with trihedral protuberances so arranged that each side ofeach of said protuberances is substantially parallel to one side of allother of said protuberances whereby the said surface is divided intothree sets of substantially parallel planes; three types of fluorescentcoatings, one type on each of said sets of planes, each of said types ofcoating ,having a naturalfluorescense in one of :the; three'-primarycolors when excited-by electrons; and a metallic coating over saidfluorescent coatings, said metallic coating being permeable to electronsonly when struck thereby at an angle substantially normal to the planethereof.

5. A fluorescent screen comprising a lightpermeableplateembossed on onesurface with trihedral protuberances so arranged that each sideofzeachof; said protuberances is substantially parallel to one side of allother of said protuberances whereby the'said surface is divided intothree-sets of substantially parallel planes; three types of fluorescentcoatings, one type on each of said-setsof planeseachof said types ofcoatinghaving a natural fluorescence in ,oneof the three primary colorswhen excited by electrons; and a metalliccoating over saidffluorescentcoatings, said metallic coating being permeable to electronsonly whenstruck thereby at an angle substantially normal to the, plane thereof;and a plurality of essentially coplanar lenses on the othersurface ofsaid plate,.each of said lenses covering an area of the platesubstantiallyequal to thearea of one of said trihedral protuberances.

6. In a ,color television system, a cathode ray tube having afluorescent screen and a plurality of electron guns for generatingelectron beams for scanning said screen, one side of said screenbeingembossed forming aplurality of, sets of fluorescent surfacesangularly disposed with respect to each other and positioned to bestruck respectively by individual ones of said electron beams, and ametallic coating, over said fluorescent. screen,.said coating beingpermeable to electrons only when struck thereby at an anglesubstantially normal to the plane thereof.

STANLEY JIKOCH. ROBERT E; RUTHERFORD.

. REFERENCES CITED The following references-are of-record inthe file ofthis patent:

UNITED STATES PATENTS Number Name Date vRe. 22,734 Rosenthal Mar. 19,1946 2,029,639 Schlesinger, Feb. 4, 1936 2,083,203 Schlesinger June.8,1937 2,121,356 ,Knoll June21, 1938 2,170,944 Glass et al Aug. 29, 19392,180,957 Hollmann Nov. 21,1939 2,195,489 Iams Apr. 2,1940 2,201,245'Ruska et a] '.May 21, 19.40 2,280,191 'I-Iergenrother Apr. 21, 19422,289,978 Malter, July 14, 1942 2,310,863 .Leverenz Feb. 9, 19432,312,792 ,Bamford .Mar. 2, 1943 2,337,980 ,Du Mont et al., Dec. 28,1943 2,367,277 jHenroteau Jan. 16, 1945 2,415,311 'Szegho Feb.4, 1947FOREIGN PATENTS Number Country Date 508,037 GreatBritain June 26, 1939562,168 Great Britain June21, 1944

